The first “A” in NASA stands for aeronautics — the science of travel through the air. It's as much about flying on airplanes and arriving safely at a destination as it is about astronauts in space. NASA's roots go back to the National Advisory Committee for Aeronautics, established in 1915 to “supervise and direct the scientific study of the problems of flight.”
NASA's work in aeronautics has made decades of contributions to aviation, national security, and the economy. Today's aviation industry relies on technology rooted in NASA research. Step onto a commercial passenger jet and you will be surrounded by some of NASA's contributions. The wings, for example, are likely descendants of the supercritical airfoils first developed in the 1960s and demonstrated in the early 1970s. The control system is a digital fly-by-wire (DFBW) system, a technology developed and first demonstrated by NASA in the early 1970s. The aircraft itself benefits from computational fluid dynamics (CFD), a way of simulating the aerodynamic flows around the aircraft. NASA aggressively pursued CFD as both a potential replacement for and a complement to wind tunnel studies.
NASA engineers also created and tested novel re-entry systems for returning space vehicles, helped develop tiltrotors, and renovated the nation's air traffic control system. NASA has also tested all types of aviation-related problems such as acoustics, aerodynamic drag, icing, vibration, crash survivability, and engine efficiency.
X-15 – The X-15 high-speed research aircraft explored the possibilities of a piloted, rocket-powered, air-launched aircraft capable of speeds about five times that of sound. Developed in a joint program among the Air Force, NASA, Navy, and North American Aviation, the X-15 program demonstrated the human desire to fly higher, faster, and beyond Earth's atmosphere. Between 1959 and 1969, the X-15 completed 199 flights, and in August 1963, the X-15 set an altitude record of 67 miles. Four years later, the aircraft set a speed record of Mach 6.7 (4,520 miles per hour).
The vehicle provided the platform for many scientific and technological studies. Featuring an exterior skin of a nickel-chrome alloy that could withstand more than 1000 °F and a structure designed for the harsh environment at hypersonic speeds, the X-15 carried out scientific research that helped prove a pilot could master the skills required for flight into space including the ability to function in a weightless environment.
The program also resulted in the first full-pressure suit to protect pilots in space, metal alloys that could survive high temperatures, new electronic and control methods for maneuvering in the thin atmospheres of near space, and knowledge of high-speed flight.
F-8 Supercritical Wing – In the late 1960s, the F-8 Supercritical Wing (SCW) concept was designed by NASA's Dr. Richard Whitcomb. Compared to a conventional wing, the Supercritical Wing was flatter on the top and rounder on the bottom, with a downward curve at the trailing edge. Its unique design reduced the effect of shock waves on the upper surface at very high speeds, which in turn reduced drag, increased flying efficiency, and helped lower fuel costs. As a result, supercritical wings are now commonplace on virtually every modern subsonic commercial transport. The SCW project flew from 1970 to 1973.
Lifting Bodies – A fleet of lifting bodies flown from 1963 to 1975 demonstrated the ability of pilots to maneuver and safely land a wingless vehicle. NASA designed these lifting bodies to test the concept of flying a wingless vehicle back to Earth from space and landing it like an aircraft at a pre-determined site. This was the technology on which the Space Shuttle was based. Aerodynamic lift — essential to flight in the atmosphere — was obtained from the shape of the vehicles rather than from wings as on a normal aircraft. The addition of fins and control surfaces allowed the pilots to stabilize and control the vehicles and regulate their flight paths.
F-16XL – As air flows over a wing, a thin layer of air normally clings to the wing surface, called the boundary layer. When that layer is laminar (smooth), it can reduce drag and the energy needed to move the wing through the air, thereby improving fuel economy and decreasing exhaust emissions in the upper atmosphere. From 1988 to 1996, NASA researchers achieved laminar flow at supersonic speeds, which informed later research into reducing drag for aircraft flying at any speed.
Computational Fluid Dynamics (CFD) – In the 1970s, NASA began developing sophisticated computer codes that could accurately predict the flow of fluids, such as air, over an aircraft's wing or fuel through a space shuttle's main engine. Those ideas and codes became computational fluid dynamics, which today is considered a vital tool for the study of fluid dynamics and the development of new aircraft.
NASTRAN – In the 1960s, NASA partnered with industry to develop a common generic software program that engineers could use to model and analyze different aerospace structures, including any kind of spacecraft or aircraft. NASA Structural Analysis (NASTRAN) is an industry-standard tool for computer-aided engineering of all types of structures.
Fly-by-Wire – In a conventional aircraft, the pilot flies the aircraft. Digital fly-by-wire (DFBW) aircraft, on the other hand, use electrical signals to transmit a pilot's inputs to the control surfaces with a computer between the two. In a sense, the pilot no longer flies the aircraft; rather, the pilot gives roll, pitch, and yaw commands, and the computer decides which combination of control surface changes will achieve the desired result. Fly-by-wire was used on the Space Shuttle and is used today on about 80% of commercial airplanes, and almost all military aircraft.
Winglets – During the 1970s and 1980s, NASA researchers made key aerodynamic advances that led to the upturned tips of wings known as “winglets.” Most modern aircraft use winglets, which increase an aircraft's range and save billions of dollars in fuel costs.
Aircraft Traffic Management – To help air traffic control centers improve the safety and efficiency of the National Airspace System, NASA developed the Future Air Traffic Management Concepts Evaluation Tool (FACET), which alerts dispatchers to forecasted demand and capacity imbalances, helping them anticipate and act to relieve congested airspace and delays at airports.
Synthetic Vision – NASA and research partners created a 3D display for pilots that provides clear vision regardless of outside conditions. The system — flying in small aircraft all over the world — creates a computer-generated view of the surroundings, as well as flight plans and feedback about the area outside of the aircraft.
Anti-Icing Fluid – An environmentally friendly anti-icing fluid invented by NASA keeps hazardous ice from building up on airplane wings, improving safety while saving time and money. The fluid is available now as a spray for automobile windshields, providing protection down to 20 °F.
Glass Cockpit – During the 1970s and 1980s, NASA created and tested the concept of an advanced cockpit display that would replace the growing number of dial and gauge instruments that were taking up space on an aircraft's flight deck. Called a “glass cockpit,” the innovative approach uses flat panel digital displays to provide the flight deck crew with a more integrated, easily understood picture of the vehicle situation. Glass cockpits are in use on commercial, military, and general aviation aircraft, and were used on the space shuttle fleet.
Passengers quietly cruising in comfort across the country at supersonic speeds, subsonic commercial airplanes that look nothing like today's classic tube-and-wing airliners, or aircraft equipped with electrically powered propulsion. It's no flight of fancy. NASA is working with its government, industry, and academic partners to design, build, and test in the air a variety of experimental X-planes that will quicken the pace for one day turning those dreams into reality.
All of this is part of NASA's New Aviation Horizons (NAH) initiative. Begun in 2016, NAH seeks to validate in the air transformational innovations examined during the past few years for reducing fuel use, emissions, and noise by the way aircraft are designed, and the way they operate in the air and on the ground.
Although the aircraft industry continues to adopt innovative technologies that are making current aircraft more energy-efficient, there's new interest in exploring alternative propulsion systems and energy sources. This new interest presents an opportunity to develop cutting-edge technologies that will dramatically reduce fuel usage, while opening up potential new markets and business opportunities for American companies and carriers.
“I feel we are at a tipping point in commercial aviation,” said Jim Heidmann, manager of NASA's Advanced Air Transport Technology Project (AATT). “We are exploring and developing game-changing technologies and concepts for aircraft and propulsion systems that can dramatically improve efficiency and reduce environmental impact, and accelerate the introduction of new aircraft.”
To provide better efficiency with less noise and fewer emissions, NASA is working with the aviation industry and academia to develop unique vehicle concepts that will use different fuselage shapes; longer, skinnier, and more blended wings; innovative materials and components; and highly integrated propulsion (engine) systems.
Through NAH, NASA is preparing to build and fly the first new X-plane, a low-boom supersonic flight demonstrator. A turboelectric aircraft configuration is among several candidates for future subsonic transport X-planes that will prove the benefits of these technologies in piloted flight within the next decade.
In research for the new plane, NASA used a technique called Schlieren photography to capture unique, measurable images of shockwaves using the Sun as a background. Seeing the shockwaves has helped NASA develop an aircraft design that minimizes their intensity and the resulting sonic boom. The F/A-18 aircraft — named the X-59 QueSST — flies at supersonic speeds and is used currently in low-sonic-boom research, performing special maneuvers to create a gentle “thump” instead of the annoying sonic boom.
According to NASA Administrator Jim Bridenstine, NASA's focus today is on taking what was learned historically and placing it in an aircraft “that can actually fly faster than the speed of sound without creating the sonic boom. And if we can accomplish that objective, then people all across the United States — and in fact, all across the world — will be able to fly faster than the speed of sound or fly multiple times the speed of sound without disrupting communities on the ground. We want to be at the very leading edge of technology when it comes to supersonic flight.”
NASA has also demonstrated technologies that achieve a significant reduction in the noise generated by standard aircraft and heard by communities near airports. The Acoustic Research Measurement (ARM) flights tested technology to address airframe noise produced by nonpropulsive parts of the aircraft during landing. The flights successfully combined several technologies to achieve a greater than 70 percent reduction in airframe noise.
NASA tested experimental designs on airframe components of a Gulfstream III research aircraft including landing gear fairings and cavity treatments as well as the Adaptive Compliant Trailing Edge (ACTE) wing flap — a flexible flap that had previously been flown as part of the ACTE project. As opposed to conventional wing flaps that typically feature gaps between the flap and the main body of the wing, the ACTE flap is a seamless design that eliminates those gaps.
The Landing Gear Noise Reduction technology element addressed airframe noise caused by airflow moving past the landing gear on approach. The experimental landing gear tested by NASA features fairings that are porous along their front, meaning they consist of many tiny holes that, in part, allow some of the air to flow through the fairing, while also deflecting some of the airflow around the landing gear.
As NASA's next six decades begin, more advances in unmanned aircraft, green aircraft, morphing wings, engine designs, and air traffic control will ensure that the agency's “first A” maintains its importance.
For more information on NASA's aeronautics programs, visit here.